Solenoid valve

ABSTRACT

The present disclosure describes a solenoid valve. The solenoid valve may have a fixed member having a tube portion. The valve may also have a mobile plunger positioned in the tube portion, the mobile plunger being axially movable between a first and a second position. The valve may also have a rod coupled to the mobile plunger and having a spool for control of fluid flow, the rod being axially movable in the tube portion. The valve may also have an electromagnetic coil positioned externally to the fixed member, where the rod has a coupling end and the mobile plunger has a coupling element where the coupling end hookingly couples to the coupling element.

This disclosure relates generally to the field of electromagneticallycontrolled valves, and particularly to the field of solenoid valves.

BACKGROUND

Valves are used in a variety of technical applications for controllingthe flow of a fluid. Electromagnetically controlled valves have anelectromagnet and by means of the electromagnet, the valve can be openedand closed.

WO0250462 discloses an electromagnetically-actuated two-way two-positionvalve that is normally closed. The valve comprises an axially-mobilegroup which has an upper end that faces a fixed group. An obturator isintercepted and then drawn in an opening movement by the mobile group. Areturn spring displaces the obturator towards a closed position when thefixed group is deactivated.

In known solenoid valves, the spool may be coupled to the mobile groupthrough a bayonet coupling. The spool may be coupled to the mobile groupthrough a transverse movement. In a first type, the bayonet couplingcomprises a through transverse path. Coupling occurs through transversemovement in a first direction. Decoupling may occur through a furthermovement in the first direction or a reverse transverse movement in asecond direction. In a second type, the bayonet coupling comprises apartially closed transverse path. Coupling occurs through transversemovement in a first direction. Decoupling occurs through a reversetransverse movement in a second direction. The present disclosure isdirected, at least in part, to improving or overcoming one or moreaspects of the prior art system.

SUMMARY

In a first aspect, the present disclosure describes a solenoid valve.The solenoid valve comprises a fixed member having a tube portion; amobile plunger positioned in the tube portion, the mobile plunger beingaxially movable between a first and a second position; a rod coupled tothe mobile plunger and having a spool for control of fluid flow, the rodbeing axially movable in the tube portion; and an electromagnetic coilpositioned externally to the fixed member, characterized in that the rodhas a coupling end and the mobile plunger has a coupling element whereinthe coupling end hookingly couples to the coupling element.

In a second aspect, the present disclosure describes a method ofassembling the solenoid valve. The method may comprise the steps ofproviding the fixed member having the tube portion and anelectromagnetic coil externally positioned on the fixed member; couplingthe rod to a mobile plunger, the rod having a spool for control of fluidflow; inserting the mobile plunger in the tube portion, the mobileplunger being axially movable between a first and a second position andthe rod being axially movable in the tube portion and hookingly couplingthe coupling end of the rod to a coupling element of the mobile plunger.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and advantages of the presentdisclosure will be more fully understood from the following descriptionof various embodiments, when read together with the accompanyingdrawings, in which:

FIG. 1 is a cross-sectional view of a solenoid valve according to thepresent disclosure;

FIG. 1A is an enlarged view of a coupling in the solenoid valve of FIG.1;

FIG. 1B is an enlarged view of a coupling, in an alternative embodiment,in the solenoid valve of FIG. 1;

FIG. 2 is a perspective view of a solenoid valve according to thepresent disclosure; and

FIG. 3 is a cross-sectional view of a further embodiment of a solenoidvalve according to the present disclosure.

DETAILED DESCRIPTION

This disclosure generally relates to a solenoid valve for control offluid flow. FIG. 1 illustrates a cross-section of the solenoid valve 10.Solenoid valve 10 is an electromagnetically actuated valve. The solenoidvalve 10 comprises a fixed member 12, a mobile plunger 14, a rod 16having a spool 18, an electromagnetic coil 20 and an air gap 22. FIG. 1illustrates a non-limiting embodiment of the solenoid valve 10 in athree position, two way proportional pressure reducing valve.

Fixed member 12 comprises a tube portion 24. Tube portion 24 has alongitudinal axis A. Tube portion 24 is hollow with a lateral wall 26surrounding bore 28. The lateral wall 26 has an internal surface 32 andan external surface 34. Tube portion 24 has an opening 30. Bore 28 isdelimited by the internal surface 32 and a base surface 33. The tubeportion 24 is axially elongated. In an embodiment, the tube portion 24may be cylindrical. Tube portion 24 is made from ferromagnetic material.In an embodiment, the tube portion 24 is at least partially made fromferromagnetic material.

The solenoid valve 10 may further comprise a valve body 36. The valvebody 36 is mounted to the fixed member 12. The valve body 36 is mountedto the tube portion 24. Valve body 36 is mounted to the opening 30 ofthe tube portion 24. Valve body 36 has a central channel 38. Channel 38has an aperture 40. Channel 38 communicates with the bore 28 through theaperture 40. Aperture 40 is formed on a first valve body end 48. Firstvalve body end 48 is positioned in the tube portion 24. The valve body36 has a second valve body end 50 formed opposite the first valve bodyend 48. Second valve body end 50 is positioned external to the tubeportion 24.

Valve body 36 has a plurality of fluid ports 52. Fluid ports 52 arepositioned external to the fixed member 12. Fluid ports 52 are spacedfrom the opening 30. Fluid ports 52 mutually communicate through thecentral channel 38. Second valve body end 50 is configured to carry atleast one fluid port 52. Further, fluid ports 52 may be positioned onthe lateral surface of the valve body 36.

In an embodiment, valve body 36 may be inserted into the bore 28. Aportion of the valve body 36 extends from the opening 30 into the bore28. In a further embodiment, the valve body 36 may be made fromferromagnetic material. Valve body 36 may serve to attract the mobileplunger 14 when the electromagnetic coil 20 is activated.

In an alternate embodiment, valve body 36 may be positioned at theopening 30. The valve body 36 does not extend from the opening 30 intothe bore 28. In yet a further embodiment, the valve body 36 may be madefrom ferromagnetic material.

In an embodiment, the fixed member 12 further comprises a plungerportion (not shown). Plunger portion is located at an end opposite tothe opening 30. The plunger portion axially extends from the tubeportion 24. Plunger portion axially extends away from the opening 30.Plunger portion and tube portion 24 may be monolithically formed. In yeta further embodiment, the plunger portion may be made from ferromagneticmaterial.

In an embodiment, the solenoid valve 10 may further comprise a fixedplunger (not shown). The fixed plunger is positioned in the tube portion24. Fixed plunger is positioned in the bore 28. Fixed plunger may befixedly positioned against the inner surface 32 of the tube portion 24.In yet a further embodiment, the fixed plunger may be made fromferromagnetic material.

The mobile plunger 14 is positioned in the fixed member 12. Mobileplunger 14 is positioned in the tube portion 24. Mobile plunger 14 isaxially movable in the tube portion 24. Mobile plunger 14 is axiallymovable in the bore 28. Mobile plunger 14 is configured to slidably movein the tube portion 24. Mobile plunger 14 may have a first end 42, asecond end 44 and a contact surface 46. Contact surface 46 is borderedby the first and second ends 42, 44 at opposite sides. Contact surface46 is in slidable contact with the internal surface 32 of the lateralwall 26 of the tube portion 24. First end 42 may abut the base surface33 of the bore 28. Second end 44 may face the mobile plunger 14. Secondend 44 may face the first valve body 36. Second end 44 may abut thefirst valve body end 48 of the valve body 36.

With respect to FIGS. 1, 1A and 2, the mobile plunger 14 comprises acoupling element 56. The second end 44 is configured to have a couplingelement 56 for coupling to rod 16. Coupling element 56 comprises a hole58. Hole 58 may be cylindrical. Hole 58 may have a height H1. Hole 58extends into the mobile plunger 14 from the second end 44. In anembodiment, the hole 58 has an offset position at the second end 44.Hole 58 has an offset position relative to the longitudinal axis A. Thecentral axis of the hole 58 is parallel to the longitudinal axis A ofthe tube portion 24. Central axis of the hole 58 is not coincident tothe longitudinal axis A of the tube portion 24.

A groove 60 is positioned at the side of the hole 58. Groove extendsfrom the hole 58. Groove 60 may be formed as a cut-out into the side ofthe hole 58. The groove 60 extends radially from the central axis of thehole 58. Groove 60 extends transversely away from the longitudinal axisA. Groove 60 may have a height H2. In an embodiment, height H2 may belonger than the height of the head 66 so as to provide for axialmovement of the head 66 in the groove 60. Groove 60 extends into themobile plunger 14 from the side of the hole 58. Groove 60 partiallyextends along a circumferential direction about the hole 58. Groove 60extends under the second end 44. A shoulder 62 separates the groove 60from the second end 44. Shoulder 62 may have a height H3. The sum of theheights H2 of the shoulder 62 and the height H3 of the groove 60 issubstantially equal to the height H1 of the hole 58.

The mobile plunger 14 is axially movable between a first and a secondposition. The mobile plunger 14 may move towards the base surface 33 tothe first position. The mobile plunger 14 may move in a first directionof travel. The mobile plunger 14 may move towards the valve body 36 tothe second position. The mobile plunger 14 may move in a seconddirection of travel. First and second positions are the extreme pointsof travel of the mobile plunger 14. In an embodiment, the limits oftravel of the mobile plunger 14 may be determined by magnetic forces.The mobile plunger 14 may be adjacent the base surface 33 at the firstposition. The mobile plunger 14 may be adjacent the valve body 36 at thesecond position. In an alternate embodiment, the limits of travel of themobile plunger 14 may be determined by the structures in the bore 28. Ina further embodiment, mobile plunger 14 may abut the base surface 33 ata first end of travel that defines the first position. Mobile plunger 14may abut the valve body 36 at a second end of travel that defines thesecond position. In an alternate further embodiment, mobile plunger 14may abut a fixed plunger at a second end of travel that defines thesecond position.

The solenoid valve 10 further comprises an elastic member 54. Elasticmember 54 is provided to return the mobile plunger 14 from anelectromagnetically actuated position. In an embodiment, the elasticmember 54 may be compressed when the mobile plunger 14 is at anelectromagnetically actuated position. In an embodiment, the elasticmember 54 may be extended when the mobile plunger 14 is at anelectromagnetically actuated position. The elastic member 54 may bepositioned between the mobile plunger 14 and the valve body 36.

With reference to FIG. 1, the rod 16 is coupled to the mobile plunger14. Rod 16 is axially elongated. The rod 16 is axially movable in thetube portion 24. Rod 16 is supported by the mobile plunger 14 in thebore 28. Rod 16 extends into the channel 38 of the valve body 36 throughaperture 40. Rod 16 is axially movable in the channel 38. Rod 16 axiallyextends along the longitudinal axis A of the tube portion 24.

Rod 16 has a coupling end 64. The coupling end 64 hookingly couples tothe coupling element 56 of the mobile plunger 14. Coupling end 64comprises a head 66 and a collar 68. Head 66 is positioned at theterminal point of the rod 66. In an embodiment, head 66 has afrustoconical shape. Head has a first portion 67 that is frustoconicaland a second portion 69 that is cylindrical. The first portion 67 iscontiguous to the second portion 69.

The head 66 is connected to a stem 70 though the collar 68. Collar 68has a reduced diameter with respect to the head 66 and the stem 70.Collar 68 has a reduced diameter with respect to the stem 70. The secondportion of the head 66 may have the same diameter to the stem 70. Head66 has a ledge 72 extending over the collar 68. Coupling end 64hookingly couples to the coupling element 56 of the mobile plunger 14through the interaction of the ledge 72 and the shoulder 62. Ledge 72hookingly engages the shoulder 62.

With reference to FIGS. 1A and 2, the head 66 fits into the hole 58.Head 66 slots into the groove 60. The head 66 remains in the groove 60as transverse movement of the head 66 is not possible. At assembly ofthe solenoid valve 10, rod 16 is assembled in the valve body 36 which isin turn positioned in the in the tube 24 thereby permitting only axialmovement of the rod 16. Ledge 72 hookingly engages the shoulder 62 whenthe head 66 slots into the groove 60. The ledge 72 abuts the internalsurface 73 of the shoulder 62. The ledge 72 may rest on the side of thegroove 60. In an embodiment, the collar 68 may rest against the shoulder62. Rod 16 moves correspondingly with the mobile plunger 14 between thefirst and second position. The rod 16 may move along the first or thesecond directions of travel with the mobile plunger 14.

With reference to FIG. 1B, in an alternative embodiment, the collar 68is configured such that the shoulder 62 engages the head 66 and the stem70. The collar 68 rests on the shoulder 62. The shoulder 62 may be heldbetween the head 66 and the stem 70. The circumferential contact surfacebetween the collar 68 and the shoulder 62 may extend to about 208degrees.

With reference to FIGS. 1 and 2, the spool 18 is positioned at anopposite end of the rod 16 relative to the coupling end 64. In anembodiment, spool 18 is integrated into the rod 16. In an alternateembodiment, spool 18 is coupled to the rod 16. The spool 18 spoolextends into the valve body 36. Spool 18 controls fluid flow through thefluid ports 52 in the valve body 36. Spool 18 moves correspondingly withthe mobile plunger 14. The spool 18 is positionable to control fluidflow through the valve body 36 as the mobile plunger 14 moves betweenthe first and second position. Spool 18 comprises fluid ports 86 and aconduit 88 for flow of fluid.

The electromagnetic coil 20 is positioned externally to the fixed member12. Electromagnetic coil 20 is positioned relative to the mobile plunger14 so as to effect actuation thereof upon activation. In an embodiment,electromagnetic coil 20 is positioned in axial correspondence to thevalve body 36 so as to effect actuation the mobile plunger 14 atactivation. Electromagnetic coil 20 is positioned to axially correspondto the valve body 36. Electromagnetic coil 20 is positioned to partiallyoverlap the valve body 36. Electromagnetic coil 20 is positioned toaxially correspond to the mobile plunger 14. Electromagnetic coil 20 ispositioned to partially overlap the mobile plunger 14. Electromagneticcoil 20 is positioned to axially correspond to the mobile plunger 14 atthe second end 44. Electromagnetic coil 20 is positioned to partiallyoverlap the second end 44 of the mobile plunger 14. Electromagnetic coil20 is positioned to axially correspond to an air gap 22. Electromagneticcoil 20 is positioned to overlap the air gap 22.

The air gap 22 is positioned in tube portion 24. The air gap 22, in thetube portion 22, is positioned between the electromagnetic coil 20 andthe mobile plunger 14. The air gap 22 is axially located along the tubeportion 24 so as to be positioned between the electromagnetic coil 20and the mobile plunger 14. The air gap 22 is positioned between theelectromagnetic coil 20 and the mobile plunger 14 in the radialdirection relative to a longitudinal axis A of the tube portion 24. Inan embodiment, the air gap 22 is positioned remote from the base surface33 of the bore 28. The air gap 22 is spaced from the valve body 36. Theair gap 22 may be positioned about the coupling of the coupling element56 and the coupling end 64. The air gap 22 encircles the coupling end 64hookingly coupled to the coupling element 56. The air gap 22 encirclesthe head 66 slotted into the groove 60.

In an alternative embodiment, the solenoid valve 10 may have a first anda second electromagnetic coils 20. The second magnetic coil 20 may bepositioned adjacent to the first electromagnetic coil 20.

A method of assembling the solenoid valve 10 may comprise the steps ofproviding the fixed member 12 having the tube portion 24; coupling therod 16 to a mobile plunger 14, the rod 16 having the spool 18 forcontrol of fluid flow; inserting the mobile plunger 14 in the tubeportion 24, the mobile plunger 14 being axially movable between a firstand a second position and the rod 16 being axially movable in the tubeportion 24; and positioning the electromagnetic coil 20 externally tothe fixed member 16, and hookingly coupling the coupling end 64 of therod 16 to a coupling element 56 of the tube portion 24.

The coupling end 64 comprises the head 66 and the coupling element 56has a hole 58. The method comprises inserting the head 66 into the hole58 along an axial direction. The head 66 is inserted in a directionalong the longitudinal axis A.

The coupling element 56 further comprises the groove 60 extending from aside of the hole 58. The method comprises slotting the head 66 into thegroove 60 along a transverse direction. The head 66 is slotted in adirection transverse to the longitudinal axis A. The valve body 36 ismounted to the rod 16 prior to the coupling of the rod 16 to the mobileplunger 14.

The skilled person would appreciate that foregoing embodiments may bemodified or combined to obtain the solenoid valve 10 of the presentdisclosure.

FIG. 3 illustrates a cross-section of a solenoid valve 100 which is avariant of the solenoid valve 10 depicted in FIG. 1. In the following,only the differences between the solenoid valve 100 of FIG. 3 and thesolenoid valve 10 of FIG. 1 are explained in detail, wherein recurringfeatures are designated with the same reference signs.

The solenoid valve 100 of FIG. 3 differs from the solenoid valve 10 ofFIG. 1 in that the solenoid valve 100 of FIG. 3 comprises twoelectromagnetic coils, namely a first coil 20 a and a second coil 20 b.The two coils 20 a, 20 b can be activated and deactivated independentlyof one another. A first end portion of the mobile plunger 14 is disposedwithin the first coil 20 a, and a second end portion of the mobileplunger 14 opposite the first end portion of the mobile plunger 14 isdisposed within the second coil 20 b.

The solenoid valve 100 of FIG. 3 further differs from the solenoid valve10 of FIG. 1 in that the solenoid valve 100 of FIG. 3 comprises a spring5 which forces the spool 18 to a defined center position 100 a relativeto the fixed valve body 36 when neither of the coils 20 a, 20 b areactivated. The center position 100 a of the spool 18 is depicted in theschematic at the top right of FIG. 3. Specifically, a first end of thespring 5 is supported by a first washer 9. The first washer 9 isconfigured to interact with a first portion of the rod 16 such as with ashoulder of the rod 16. The first washer 9 is further configured tointeract with a first portion of the fixed valve body 36 such as with afirst shoulder of the valve body 36. A second end of the spring 5opposite the first end of the spring 5 is supported by a second washer10. The second washer 10 is configured to interact with a second portionof the rod 16 such as with a portion of the spool 18. The second washer10 is further configured to interact with a second portion of the fixedvalve body 36 such as with a second shoulder of the valve body 36.

When the electromagnetic coils 20 a, 20 b are not activated, the spring5 and the washers 9, 10 interact with the rod 16 and with the fixedvalve body 36 to force the mobile plunger 14 and the spool 18 to theircenter position with respect to the fixed valve body 36. When the spool18 is in its center position 100 a, the spool 18 provides fluidcommunication between the side port 3 and the front port 1 of the fixedvalve body 36 while fluidly isolating the side ports 2 and 4 of thevalve body 36 from the ports 1 and 3 and from one another.

When only the first coil 20 a is activated, the first coil 20 a forcesthe mobile plunger 14 toward the left in FIG. 3 and toward the basesurface 33 of the tube portion 24. Due to the coupling between themobile plunger 14 and the rod 16 as depicted in FIGS. 1A and 1B above,the mobile plunger 14 drags the rod 16 and the spool 18 toward the left,thereby forcing the spool 18 to its second position 100 b. When thespool 18 is in its second position 100 b, the spool 18 provides fluidcommunication between the ports 1 and 4 and between the ports 2 and 3,respectively. When the first coil 20 a is deactivated, the spring 5again forces the spool 18 to its center position 100 a.

When only the second coil 20 b is activated, the second coil 20 b forcesthe mobile plunger 14 toward the right in FIG. 3 and toward the end 48of the fixed valve body 36. Due to the coupling between the mobileplunger 14 and the rod 16, the mobile plunger 14 pushes the rod 16 andthe spool 18 toward the right, thereby forcing the spool 18 to its thirdposition 100 c. When the spool 18 is in its third position 100 c, thespool 18 provides fluid communication between the ports 1 and 2 andbetween the ports 3 and 4, respectively. When the second coil 20 b isdeactivated, the spring 5 again forces the spool 18 to its centerposition 100 a.

INDUSTRIAL APPLICABILITY

This disclosure describes a solenoid valve 10 and a solenoid valve 100having a hooking type coupling system that couples the rod 16 to thetube portion 24. The hooking type coupling has the advantage ofincreasing the speed of assembly and of recovering the radial clearance,without increasing the axial clearance which affect the movement of themobile plunger. The hooking type coupling between the coupling element56 wherein the coupling end 64 results in less ferromagnetic materialbeing removed from the mobile plunger 14. Removal of excessferromagnetic material negatively reduces the electromagnetic forces.Removal of less ferromagnetic material in the magnetic field closingzone allows the maximum efficiency of the magnetic force to bemaintained. The solenoid valves 10, 100 that have the mobile plunger 14connected to the spool 18 ensure greater stability in dynamic operationas the said components always move together and without any delay beingimparted from one component to another.

Accordingly, this disclosure includes all modifications and equivalentsof the subject matter recited in the claims appended hereto as permittedby applicable law. Moreover, any combination of the above-describedelements in all possible variations thereof is encompassed by thedisclosure unless otherwise indicated herein.

Where technical features mentioned in any claim are followed byreference signs, the reference signs have been included for the solepurpose of increasing the intelligibility of the claims and accordingly,neither the reference signs nor their absence have any limiting effecton the technical features as described above or on the scope of anyclaim elements.

One skilled in the art will realize the disclosure may be embodied inother specific forms without departing from the disclosure or essentialcharacteristics thereof. The foregoing embodiments are therefore to beconsidered in all respects illustrative rather than limiting of thedisclosure described herein. Scope of the invention is thus indicated bythe appended claims, rather than the foregoing description, and allchanges that come within the meaning and range of equivalence of theclaims are therefore intended to be embraced therein.

1-10. (canceled)
 11. A solenoid valve (10) comprising: a fixed member(12) having a tube portion (24); a mobile plunger (14) positioned in thetube portion (24), the mobile plunger (14) being axially movable betweena first and a second position; a rod (16) coupled to the mobile plunger(14) and having a spool (18) for control of fluid flow, the rod (16)being axially movable in the tube portion (24); and an electromagneticcoil (20) positioned externally to the fixed member (16), wherein therod (16) has a coupling end (64) and the mobile plunger (14) has acoupling element (56) wherein the coupling end (64) hookingly couples tothe coupling element (56).
 12. The solenoid valve (10) of claim 11wherein the coupling element (56) is positioned at a second end (44) ofthe mobile plunger (14) and comprises a hole (58).
 13. The solenoidvalve (10) of claim 12 wherein the coupling element (56) comprises agroove (60) extending from the hole (58).
 14. The solenoid valve (10) ofclaim 13 wherein the coupling end (64) comprises a head (66) and acollar (68) wherein the head (66) engages into the groove (60).
 15. Thesolenoid valve (10) of claim 14 wherein the coupling element (56)comprises a shoulder (62) and the coupling end (64) comprises a ledge(72), the ledge (72) hookingly engages the shoulder (62).
 16. Thesolenoid valve (10) of claim 15 further comprising an air gap (22)positioned in tube portion (24) between the electromagnetic coil (20)and the mobile plunger (14), wherein the air gap (22) is positionedabout the coupling end (64) hookingly coupled to the coupling element(56).
 17. The solenoid valve (10) of claim 16 wherein the air gap (22)encircles the head (66) slotted into the groove (60).
 18. A method ofassembling the solenoid valve (10) comprises the steps of: providing afixed member (12) having a tube portion (24) and having anelectromagnetic coil (20) externally positioned on the fixed member(16); coupling a rod (16) to a mobile plunger (14), the rod (16) havinga spool (18) for control of fluid flow; and inserting the mobile plunger(14) in the tube portion (24), the mobile plunger (14) being axiallymovable between a first and a second position and the rod (16) beingaxially movable in the tube portion (24); wherein
 19. The method ofclaim 18 wherein the coupling end (64) comprises a head (66) and thecoupling element (56) has a hole (58) and further comprising the step ofinserting the head (66) into the hole (58) along an axial direction. 20.The method of claim 19 wherein the coupling element (56) furthercomprises a groove (60) extending from a side of the hole (58) furthercomprising the step of slotting the head (66) into the groove (60) alonga transverse direction.